冶炼厂周边农田铜镉污染现状及修复效果评价

Status and Remediation Assessment of Cu/Cd Pollution in Farmland Area around Smelter

摘要: 基于表层土壤重金属实测值，运用数理统计、地累积指数法与GIS相结合的方法对冶炼厂周边农田土壤污染现状与修复效果进行分析评价。结果表明：1) 冶炼厂周边农田土壤Cu、Cd均有不同程度的污染，Cu的地累积污染指数范围为1.66~4.80，污染级别为中~极强，以强污染为主；Cd的地累积污染指数范围为0.61~2.91，污染级别为无~强，以中~强污染为主。2) 修复后土壤pH显著升高；土壤中Cu、Cd形态由植物可利用态向潜在可利用态转变；土壤Cu、Cd有效态降幅为均在50%以上，其中Cu的降幅范围为54.5%~85.0%，Cd的降幅范围为50.0%~64.1%；土壤Cu、Cd生物有效性系数均降低，Cu降低范围为5.3%~19.6%，Cd降低范围为19.2%~41.4%。3) 土壤Cu、Cd全量与有效态含量空间分布规律相似，都呈辐射分布格局，全量与有效态之间呈显著正相关关系，修复前pH与有效态之间呈正相关关系，修复后呈负相关关系。

Abstract: The status investigation and remediation evaluation at cultivated land surrounding smelting fac-tory are performed through employing the mathematical statistics and geoaccumulation index method based on the coupling the GIS technology. The results show that: 1) The different degrees on Cu/Cd pollution emerge in the investigated region, in which the range of I-geo for Cu pollution was located in 1.66~4.80 and belonged to the middle-extremely serious pollution degree, display-ing the main characteristics of the serious pollution in the investigated region; in which Cd pollution belonged to the none-serious pollution degree with 0.61~2.91 I-geo, displaying the main characteristics of the middle-serious pollution. 2) After the repair was significantly increased soil pH; soil Cu, Cd form can be used by plants potentially available to the state transition; soil Cu, Cd effective decline of state in more than 50%, a decline of the range in which the Cu is 54.5%~85.0%, Cd decline in the range of 50.0%~64.1%, and the decline in the effective state of higher Cu Cd; soil Cu, Cd bioavailability factor decreased, Cu reduces the range of 5.3%~19.6%, Cd reduce the range of 19.2%~41.4%. 3) Soil Cu/Cd total concentration and availability spatial distribution, significantly positively related, both show radiation distribution pattern. Soil pH is significantly positively related with Cu/Cd availability before remediation whereas significant positive correlation after remediation.